Update free-programming-books.md

Fixed typo.
[es] Added MOOC ~ Cursos masivos en linea, section
Add book on Backbone.js, sort Backbone books

Added: Building Single Page Web Apps with Backbone.js
Fix sorting order
Merge branch 'master' of github.com:vhf/free-programming-books
[es] Cleanup & reorganizing link (sort & remove duplicated)
dodaje pythona, c, c++, sql
Adding AJAX to the list. Edit some books positions to be consistent with: CONTRIBUTING.md
Merge pull request #687 from matysanchez/master

Adding AJAX to the list. Edit some books positions to be consistent with: CONTRIBUTING.md
Merge pull request #686 from agilob/patch-1

adding python, c, c++, sql to the list in Polish
Merge pull request #681 from JIghtuse/master

Add book on Backbone.js, sort Backbone books
spelling
Merge pull request #689 from borgified/master

LICENCE->LICENSE
Better formating (2 spaces between sections)
fix broken url
Merge pull request #690 from borgified/fix_url

fix broken url
Merge pull request #684 from esparta/master

[es] Updated info
Adding Turkish Rust book

named "Rust'a Giriş"
Added Indonesian language support
Fixed Broken URL

Fixed issue https://github.com/borgified/test_issue/issues/53